drivers/ieee1394/dma.c

   1 /*
   2  * DMA region bookkeeping routines
   3  *
   4  * Copyright (C) 2002 Maas Digital LLC
   5  *
   6  * This code is licensed under the GPL.  See the file COPYING in the root
   7  * directory of the kernel sources for details.
   8  */
   9
  10 #include <linux/mm.h>
  11 #include <linux/module.h>
  12 #include <linux/pci.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/scatterlist.h>
  15
  16 #include "dma.h"
  17
  18 /* dma_prog_region */
  19
  20 void dma_prog_region_init(struct dma_prog_region *prog)
  21 {
  22         prog->kvirt = NULL;
  23         prog->dev = NULL;
  24         prog->n_pages = 0;
  25         prog->bus_addr = 0;
  26 }
  27
  28 int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
  29                           struct pci_dev *dev)
  30 {
  31         /* round up to page size */
  32         n_bytes = PAGE_ALIGN(n_bytes);
  33
  34         prog->n_pages = n_bytes >> PAGE_SHIFT;
  35
  36         prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
  37         if (!prog->kvirt) {
  38                 printk(KERN_ERR
  39                        "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
  40                 dma_prog_region_free(prog);
  41                 return -ENOMEM;
  42         }
  43
  44         prog->dev = dev;
  45
  46         return 0;
  47 }
  48
  49 void dma_prog_region_free(struct dma_prog_region *prog)
  50 {
  51         if (prog->kvirt) {
  52                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
  53                                     prog->kvirt, prog->bus_addr);
  54         }
  55
  56         prog->kvirt = NULL;
  57         prog->dev = NULL;
  58         prog->n_pages = 0;
  59         prog->bus_addr = 0;
  60 }
  61
  62 /* dma_region */
  63
  64 /**
  65  * dma_region_init - clear out all fields but do not allocate anything
  66  */
  67 void dma_region_init(struct dma_region *dma)
  68 {
  69         dma->kvirt = NULL;
  70         dma->dev = NULL;
  71         dma->n_pages = 0;
  72         dma->n_dma_pages = 0;
  73         dma->sglist = NULL;
  74 }
  75
  76 /**
  77  * dma_region_alloc - allocate the buffer and map it to the IOMMU
  78  */
  79 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
  80                      struct pci_dev *dev, int direction)
  81 {
  82         unsigned int i;
  83
  84         /* round up to page size */
  85         n_bytes = PAGE_ALIGN(n_bytes);
  86
  87         dma->n_pages = n_bytes >> PAGE_SHIFT;
  88
  89         dma->kvirt = vmalloc_32(n_bytes);
  90         if (!dma->kvirt) {
  91                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  92                 goto err;
  93         }
  94
  95         /* Clear the ram out, no junk to the user */
  96         memset(dma->kvirt, 0, n_bytes);
  97
  98         /* allocate scatter/gather list */
  99         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
 100         if (!dma->sglist) {
 101                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
 102                 goto err;
 103         }
 104
 105         sg_init_table(dma->sglist, dma->n_pages);
 106
 107         /* fill scatter/gather list with pages */
 108         for (i = 0; i < dma->n_pages; i++) {
 109                 unsigned long va =
 110                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 111
 112                 sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va),
 113                                 PAGE_SIZE, 0);
 114         }
 115
 116         /* map sglist to the IOMMU */
 117         dma->n_dma_pages =
 118             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 119
 120         if (dma->n_dma_pages == 0) {
 121                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 122                 goto err;
 123         }
 124
 125         dma->dev = dev;
 126         dma->direction = direction;
 127
 128         return 0;
 129
 130       err:
 131         dma_region_free(dma);
 132         return -ENOMEM;
 133 }
 134
 135 /**
 136  * dma_region_free - unmap and free the buffer
 137  */
 138 void dma_region_free(struct dma_region *dma)
 139 {
 140         if (dma->n_dma_pages) {
 141                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 142                              dma->direction);
 143                 dma->n_dma_pages = 0;
 144                 dma->dev = NULL;
 145         }
 146
 147         vfree(dma->sglist);
 148         dma->sglist = NULL;
 149
 150         vfree(dma->kvirt);
 151         dma->kvirt = NULL;
 152         dma->n_pages = 0;
 153 }
 154
 155 /* find the scatterlist index and remaining offset corresponding to a
 156    given offset from the beginning of the buffer */
 157 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 158                                   unsigned int start, unsigned long *rem)
 159 {
 160         int i;
 161         unsigned long off = offset;
 162
 163         for (i = start; i < dma->n_dma_pages; i++) {
 164                 if (off < sg_dma_len(&dma->sglist[i])) {
 165                         *rem = off;
 166                         break;
 167                 }
 168
 169                 off -= sg_dma_len(&dma->sglist[i]);
 170         }
 171
 172         BUG_ON(i >= dma->n_dma_pages);
 173
 174         return i;
 175 }
 176
 177 /**
 178  * dma_region_offset_to_bus - get bus address of an offset within a DMA region
 179  *
 180  * Returns the DMA bus address of the byte with the given @offset relative to
 181  * the beginning of the @dma.
 182  */
 183 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 184                                     unsigned long offset)
 185 {
 186         unsigned long rem = 0;
 187
 188         struct scatterlist *sg =
 189             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 190         return sg_dma_address(sg) + rem;
 191 }
 192
 193 /**
 194  * dma_region_sync_for_cpu - sync the CPU's view of the buffer
 195  */
 196 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 197                              unsigned long len)
 198 {
 199         int first, last;
 200         unsigned long rem = 0;
 201
 202         if (!len)
 203                 len = 1;
 204
 205         first = dma_region_find(dma, offset, 0, &rem);
 206         last = dma_region_find(dma, rem + len - 1, first, &rem);
 207
 208         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 209                                 dma->direction);
 210 }
 211
 212 /**
 213  * dma_region_sync_for_device - sync the IO bus' view of the buffer
 214  */
 215 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 216                                 unsigned long len)
 217 {
 218         int first, last;
 219         unsigned long rem = 0;
 220
 221         if (!len)
 222                 len = 1;
 223
 224         first = dma_region_find(dma, offset, 0, &rem);
 225         last = dma_region_find(dma, rem + len - 1, first, &rem);
 226
 227         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
 228                                    last - first + 1, dma->direction);
 229 }
 230
 231 #ifdef CONFIG_MMU
 232
 233 static int dma_region_pagefault(struct vm_area_struct *vma,
 234                                 struct vm_fault *vmf)
 235 {
 236         struct dma_region *dma = (struct dma_region *)vma->vm_private_data;
 237
 238         if (!dma->kvirt)
 239                 return VM_FAULT_SIGBUS;
 240
 241         if (vmf->pgoff >= dma->n_pages)
 242                 return VM_FAULT_SIGBUS;
 243
 244         vmf->page = vmalloc_to_page(dma->kvirt + (vmf->pgoff << PAGE_SHIFT));
 245         get_page(vmf->page);
 246         return 0;
 247 }
 248
 249 static const struct vm_operations_struct dma_region_vm_ops = {
 250         .fault = dma_region_pagefault,
 251 };
 252
 253 /**
 254  * dma_region_mmap - map the buffer into a user space process
 255  */
 256 int dma_region_mmap(struct dma_region *dma, struct file *file,
 257                     struct vm_area_struct *vma)
 258 {
 259         unsigned long size;
 260
 261         if (!dma->kvirt)
 262                 return -EINVAL;
 263
 264         /* must be page-aligned (XXX: comment is wrong, we could allow pgoff) */
 265         if (vma->vm_pgoff != 0)
 266                 return -EINVAL;
 267
 268         /* check the length */
 269         size = vma->vm_end - vma->vm_start;
 270         if (size > (dma->n_pages << PAGE_SHIFT))
 271                 return -EINVAL;
 272
 273         vma->vm_ops = &dma_region_vm_ops;
 274         vma->vm_private_data = dma;
 275         vma->vm_file = file;
 276         vma->vm_flags |= VM_RESERVED | VM_ALWAYSDUMP;
 277
 278         return 0;
 279 }
 280
 281 #else                           /* CONFIG_MMU */
 282
 283 int dma_region_mmap(struct dma_region *dma, struct file *file,
 284                     struct vm_area_struct *vma)
 285 {
 286         return -EINVAL;
 287 }
 288
 289 #endif                          /* CONFIG_MMU */